Study On Characteristics And Function Of Biofilms In The Muti-Layed Biological Filter

Novel multi-layered biological trickling filter is a new technology ofsewage treatment in rural areas. It is developed by our research team andhas a broad application prospect. Compared with the traditional biologicaltrickling filter, multi-layered biological trickling filter is moremanageable and nonexistence of blocking, and it has a higher removalefficiency, a smaller floor area, a lower running cost. It is considered as agood technology in dealing with sewage in rural areas.The main mechanism of multi-layered biological trickling filter isthe metabolism of microorganism in the biomembrane in the surface ofthe filter media. Generally speaking, the biofilm activity has a directeffect on the treatment efficiency of sewage. The characteristics ofbiomembrane have not yet been studied in multi-layered biological filter,although they had been extensively researched in other sewage treatmentprocesses in the recent years.This paper compared and discussed the performance of bothmulti-layered biological filter and traditional trickling filter, in order toknow the differences of the removal efficiency, the pH changes, thedissolved oxygen, the biofilm biomass, the dehydrogenase activity ofbiomembrane and nitrification between them.Our results show that the multi-layered biological filter has asignificant advantage in the removing of COD and ammonia nitrogen. Ithas the ability to resist the high organic load. Meanwhile, the effluentquality of the multi-layered biological filter can be stable easily and has asmall fluctuation and high removal efficiency.Through the comparison of dissolved oxygen content in the two trickling bio-filters, we can see that the multi-layered biological filter ismore conducive to the flow of air. The high content of dissolved oxygenis more conducive to microbial metabolism and reproduction, so thebiofilm mass in multi-layered biological filter is significantly higher thanthat in the normal biological trickling filter.Multi-layered biological filter has a higher dehydrogenase activity.These correspond to the result of contaminant removal efficiency.In a word，compared to the traditional bio-trickling filter, themulti-layered biological filter has a good advantage in biofilm activityand sewage treatment. Our research not only supplies the theoreticalfoundation to the application of the multi-layered biological filter, butalso indicates the future study on the microbial population and itsmechanisms of action in the multi-layered biological filter.